Features: Achieve precise drilling accuracy with these 7PCS drill bit collars featuring depth stop rings that prevent deviation during operations, suitable for 3-12mm bits across wood, metal, and plastic materials. Crafted from hardened aluminum alloy bodies and 304 stainless steel set screws, this versatile set offer corrosions resistant performances and quick adjust functionality for effortless installation. Ideal for professional woodworkers, metal fabricators, and enthusiasts requiring millimeter levels precisions in drilling applications. Perfect for workshop projects, construction sites, or home repairs where consistent hole depth and alignment are critical for materials like cabinetry, plumbing fixtures, or automotive parts. The comprehensive 7 piece drill guide accessory set ensures reliability through materials construction while maintaining drilling accuracy across multiple job types. Specifications: Component:Alloy + Stainless Steel Inner diameter dimensions: 3/4/5/6/8/10/12mm Package Includes: 7Pcs Depth Stop Rings 1Piece Small Wrench note: Please allow 1mm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual color of the item.